1. Field of the Invention
The present invention relates to a printed circuit board (PCB) for manufacturing a semiconductor package, and more particularly, to a thin PCB for manufacturing a chip scale package (CSP).
2. Description of the Related Art
In recent years, as most electronic products including various portable data communication devices, such as personal computers, cellular phones, and personal data terminals, have been scaled down and become more light-weight and efficient, their data processing capacities have increased. Thus, using a chip scale package (CSP) technique, a semiconductor chip can be assembled in a semiconductor package having a size similar to or slightly larger than the chip size. CSP techniques vary according to manufacturing methods, for example, a thin PCB method of manufacturing a CSP. In this method, semiconductor packages comprise a semiconductor chip manufactured with a thin PCB. However, the thickness (e.g., 0.17 mm or less) of a conventional thin PCB for manufacturing a CSP is typically smaller than that (e.g., 3 mm) of a conventional PCB for manufacturing a typical semiconductor package.
FIGS. 1 through 3 are diagrams illustrating problems of a conventional thin PCB. As shown in FIG. 1, in a conventional thin PCB 10, a plurality of unit PCBs 10a, 10b, and 10c are connected in a row. Although only three exemplary unit PCBs 10a, 10b, and 10c are illustrated in FIG. 1, the thin PCB 10 can include a greater number of unit PCBs. Circuit patterns 11a, 11b, and 11c are disposed in the unit PCBs 10a, 10b, and 10c, respectively. A plurality of holes (not shown) are formed in each of the circuit patterns 11a, 11b, and 11c. A plurality of holes or slots 12 are vertically arranged at interfaces between adjacent unit PCBs, for example, between the unit PCBs 10a and 10b or 10b and 10c. These holes or slots 12 suppress distortion of the PCB 10. A plurality of holes 13 are formed in an upper portion of the thin PCB 10, and a plurality of holes 14 are formed in a lower portion thereof. These holes 13 and 14 are used as recognition marks for a package manufacturing apparatus and may be used for alignment of the thin PCB 10 when the thin PCB 10 is transferred.
As described above, the thin PCB 10 has a relatively small thickness. Thus, the thin PCB 10 is flexible and makes it difficult to manufacture semiconductor packages. Thus, one solution shown in FIG. 2 was proposed. That is, semiconductor packages are manufactured using a carrier 20 supporting a thin PCB 10. In this method, since the thin PCB 10 is supported by the carrier 20, it is inflexible during package manufacturing processes. The carrier 20 can be formed of an inflexible material, for example, a sus material. A vacant space 23 is located in the center of the carrier 20 so as to expose the rear surface of the thin PCB 10. The carrier 20 is a kind of frame that surrounds the vacant space 23. Holes 21 are formed on both lateral surfaces of the carrier 20, and a mark 22 is formed on an edge thereof. The holes 21 and the mark 22 are used as recognition marks and may be used for alignment of the carrier 20 when the carrier 20 is transferred.
As shown in FIG. 3, in order to adhere the thin PCB 10 to the carrier 20, the thin PCB 10 is first mounted on the carrier 20. Only the upper and lower portions of the thin PCB 10 overlap upper and lower portions of the carrier 20 and are supported by the carrier 20, and the remaining portion of the thin PCB 10 do not overlap the carrier 20. Next, the thin PCB 10 is secured to the carrier 20 by an adhesive 31. The adhesive 31 is applied to the upper and lower portions of the thin PCB 10 and the upper and lower portions of the carrier 20.
As described above, since the conventional thin PCB 10 has a very small thickness, it should be adhered to a supporting portion such as the carrier 10 and used in package manufacturing processes. Thus, prior to the package manufacturing processes, additional processes of aligning and adhering the thin PCB 10 to the carrier 20 should be performed. Also, after a semiconductor package is completed, a process of removing the adhesive 31 from the carrier 20 should be further performed to reuse the carrier 20.